Noting that the above secure beamformer designs require the knowledge of the eavesdropper's CSI, which is not always available in practical applications.
In such cases, artificial noise (AN) technology was introduced to realize PLS [1]}, which uses a large amount of additional energy to generate interfering signals for disrupting potential malicious receptions.
The existing communication literature generally forces the AN to be uniformly distributed onto the null space of the confidential transmission channels to disturb the eavesdropper's reception but not harm legitimate users [2]}.
Inspired by this concept, in addition to realizing the respective performance requirements of communication and radar systems, the residual power can be used to generate AN. However, this null space projection design can only exploit limited spatial DoFs to generate AN, especially for a system with many users.
In recent works [3]}, [4]}, the AN and transmit beamforming were jointly optimized to implement secure DFRC transmissions, making full use of available DoFs for generating AN.
In addition, the authors in [5]} proposed to enhance secure performance by deploying an RIS in DFRC systems.
However, how to ensure the physical layer security in RCC systems remains an open problem.
Instead of consuming additional power to generate AN, the authors in [6]} proposed to exploit the inherent multi-user interference as a helpful resource by converting it to act like AN or distributed friendly jammers to improve the security performance.
Inspired by the concept of interference exploitation, the radar signal, which usually has very strong signal power, is an up-and-coming candidate as the jamming signal to enhance the physical layer security performance for the considered RCC system.
